Flexible link pipe wrench



Dec. 13, 1955 T. PETERSEN FLEXIBLE LINK PIPE WRENCH Filed June 1, 1954 INVENTOR. W @Z Ldw WA W United States Patent FLEXIBLE LINK PIPE WRENCH Thorvald Petersen, Erie, Pa., assignor to Reed Manufacturing Company, Erie, Pa., a corporation of Pennsylvania Application June 1, 1954, Serial No. 433,774

2 Claims. (Cl. 81-68) This invention is a chain pipe wrench having a head with convex gripping surfaces on its lower face tangent to the ends of the head and with chain slots extending into the head above the gripping surfaces so the entire length of the teeth is available for gripping. The chain slot receiving the intermediate part of the chain extends over the top of the head and has three pairs of hooks which receive the chain pins and adjustably anchor the chain to the head.

In the accompanying drawing, Fig. 1 is a side view of the pipe wrench; Fig. 2 is a sectional side elevation; and Fig. 3 is a bottom view.

The pipe wrench has a handle 1 having at its front end a head 2 provided with a seat 3 for a pipe jaw 4 which is secured to the seat by a set screw 5. The seat 3 is offset to one side of the handle and extends longitudinally of the handle and has a width substantially the same as the thickness of the handle. At the center of the seat 3 is a projection 6 which fits into a groove 7 in the pipe jaw and keeps the jaw in alignment with the seat.

At the front and back of the head 2 are chain receiving slots 8 and 9 which are substantially in alignment with the handle 1. The slot 9 at the back of the head extends inward into the head and terminates at the seat 3 for the jaw. Across the slot 9 is fixed one of the pins 10 of a link chain 11 thereby anchoring one end of the chain to the head. At the front of the head, the slot 8 likewise extends into the head and has its lower end terminating at the seat 3 for the jaw. The slot 9 is inclined inwardly from the front of the head and has on its sides three pairs of hooks 12, 13, and 14 which are spaced along the length of the slot 8 in such a manner as to receive three of the pins 15 at an intermediate portion in the length of the link chain 11. The purpose of the three pairs of hooks 12, 13, and 14 is to insure that at least two of the hooks will be effective in shear in holding the chain. Since the chain is made up of alternate inner links 11a and outer links 11b, the pins 15 are stressed differently by the different links. Tension in the outer links 11b stresses the pins in shear. Tension in the inner links introduces a bending stress. The hook construction cannot be conveniently made as strong as the fixed slot at the back of the head permanently anchoring one end of the chain. By reason of the hooks, the chain can be adjusted to accommodate a wide varity of pipe sizes.

The jaw 4 has at its front end a convex arcuate toothed gripping surface 16 centered at point 17 and having its front end merging smoothly or tangent to an end surface 18 at the front of the head. The gripping surface is not necessarily precisely arcuate but an are centered on 17 generally defines the outline. In the front end of the jaw is a slot 8:: complementary to the slot 8 in the head. The slot 8a has the same inclination as the slot 8 and extends inwardly from the front end 18 and terminates at the surface of the jaw resting on the seat 3. At the back end of the jaw is a similar arcuate toothed gripping surface 16a centered at point 17a and merging smoothly into the end 2,726,564 Patented Dec. 13, 1955 surface 18a on the head. In the back surface of the jaw there is likewise a slot 9 1 complementary to the slot 9 in the head and extending inward into the jaw and terminating at the surface of the jaw seated on the seat 3. As is apparent from the bottom view in Fig. 3, the slots 8a and 9a in the jaws cut slightly into the jaws, but are clear of all but the extreme ends of the toothed gripping surfaces 16 and 16a so that the entire length of the teeth or the entire width of the jaw is normally effective in gripping pipe. The convex formation of the gripping surfaces 16 and 16a substantially improves the gripping and at the same time cuts down on the necessary physical dimensions of the wrench, which is very important in pipe wrenches which must be frequently used in cramped quarters.

The improved gripping surfaces of the pipe jaws are obtained by locating the centers of the gripping surfaces 17 and 17a within the head and between the pin 10 and the lowermost hook 12. There are straight end surfaces 19 and 19a at the front and back of the jaw which are substantially direct continuations of the surfaces 18 and 18a on the head and against which the pins of the link chain 11 may rest under certain conditions. This keeps the pins 15 clear of the teeth. The location of the centers 17 and 17a also makes the end surfaces 18, 19, and 18a, 19a substantially normal to the seat 3 for the jaw which likewise is desirable in case the pins of the link chain 11 rest against these surfaces. By having the toothed gripping surface 16, 16a between and generally tangent to the end surfaces 19, 19a and arcuate about centers on the head, the physical size of the head is greatly reduced and the teeth grip the pipe with a smaller movement of the handle than with prior art wrenches where the centers of the gripping surfaces are offset to one side of the head. Also, the stresses in the head are more effectively taken in applicants wrench because the stresses are localized in the head.

In the use of the pipe wrench, the free end of the chain is wrapped around the pipe and engaged in the hook members 12, 13, and 14. Because of the inclination of the slot 8 at the front of the head, the chain naturally falls into place with the excess length lying along the upper side of the handle 1. The wrench can now be used like a conventional pipe wrench, the surface 16 being used for screwing pipe in one direction and the surface 16:: being used for screwing pipe in the opposite direction. The

convex gripping surfaces 16 and 16a with the teeth extend-' ing clear across the surfaces provide an effective grip on the pipe. Since the width of the gripping surfaces 16, 16a is substantially the same as the thickness of the handle, the wrench takes up a minimum of space which is an important advantage.

What is claimed as new is:

1. In a chain pipe wrench, a handle having at its front end a head with convex toothed gripping surfaces offset to the lower side of the handle and at the front and back of the head, said head having front and back end surfaces, the gripping surfaces being arcuate about centers on the head and between said end surfaces of the head and generally tangent to said end surfaces, a chain, and means anchoring the chain at points inward from the end surfaces of the head.

2. The wrench of claim 1 in which the head has a jaw seat offset to one side and extending lengthwise of the handle and the convex tooth gripping surfaces are on a jaw fixed to the head and having a seating surface seated on the jaw seat, said head having chain receiving slots extending into'the head at the front and back ends of the jaw seat, said jaw having complementary chain receiving slots extending into the seating surface of the jaw and overlying the slots in the head, the jaw and head having end surfaces normal to the jaw seat, said chain having pinned links, a fixed anchor at the back end of the head References Cited in the file of this patent 5 UNITED STATES PATENTS 483,419 Brock Sept. 27, 1892 Mahnicke Feb. 13, 1894 Farrell Aug. 23, 1910 Carll Mar. 28, 1922 

